Help me troubleshoot a ticking sound (with videos)

[Andy135]

After a brief outing this morning I noticed a ticking sound as I wheeled the 7 back into the garage. What could it be?

Some observations:

1. It's occurring in the vicinity of the offside rear wheel.
2. The tick is loudest, or only audible, for about 90 degrees of a wheel rotation.
3. The tick can be physically felt at the wheel, hub and driveshaft, and most strongly felt at the hub.
4. There is no discernible play in the propshaft UJ's, so I think this can be ruled out.

Here are a couple of videos where you can clearly hear the tick.

I have a theory but to avoid leading the witness I'll keep it to myself unless/until others suggest the same potential cause.

[Jonathan Kay]

Wheel balance weight?

Speedometer sensor?

Jonathan

[Andy135]

Good suggestions Jonathan, but the second video shows the tick present with the wheel off the car, so that rules out a wheel weight. I should have stated in the original post that I also tested the speed sensor theory by winding it away from the reluctor ring - sadly the tick was still present.

[Wrightpayne]

Are the disc ti drive flange bolts all tight.

Check routing of the handbrake cable

[David aka Blue7]

More like a clunk than a tick and sounds like something in the dif' which is making contact with the outer casing and amplifying the sound.   If you place your hand on the dif casing while someone turns the wheel you should be able to feel any vibrations / knocking within.

[Beagler]

Try the old long screwdriver to your ear test like a stethescope and move it from one component to another while driveshaft is turning. 

[John Vine]

Interesting recordings.  It does indeed sound much more like a metallic clunk than a tick. 

Some questions:

Do you have an LSD/ATB?  If so, which one?

Is the diff oil at the correct level?

Noises like yours can transmit very easily from one component to another, especially in the drivetrain.  Can you get an assistant to turn the wheel/hub while you lie under the car with (as suggested) a long screwdriver (or better still, stethoscope)?

If I had to take a punt, I'd say the diff (or something inside) was prime suspect.  I hope I'm wrong!

JV

[Andy135]

#4, just checked the disc to flange bolts and they seem fine. Right pigs to get at though. Handbrake cable clear of any rotating components.

#5, yes, it could be described as a clunk when up close. Sounds more tick-like when pushing the car by hand. When I had it in the air earlier and with my son turning the wheel with me underneath I couldn't feel anything at all on the nearside drive shaft or diff casing, but felt the tick/clunk very clearly on the offside drive shaft, and clearer still on the offside hub, which suggests it's unrelated to the diff. For what it's worth it's a LSD so potentially rather expensive if it does prove to be diff-related. Might check again later on, paying more attention to the diff casing just to be sure.

#6, yes, might need to use a stethoscope tool to confirm what I can feel of the tick/clunk.

Further info for what it's worth - there's no noticeable play when wiggling the road wheel with hands at 3 and 9 o'clock. I was checking for play in the bearing but there's no bearing whine that usually comes along with a failing bearing.

[Andy135]

#7, looks like our posts crossed. Yes, it's a LSD of unknown design. Can feel the clunk strongly at the wheel hub, less strongly at the driveshafts and I don't remember feeling it at the diff casing but per my last post I'll check again.

[John Vine]

#9  Yes, it's a LSD of unknown design.

The only way to be sure is to remove a driveshaft (ideally both) and peer into the diff.  See here for the various types.

For info, a Quaife ATB can make clicking noises as you push the car backwards or forwards.  This is normal.

However, if the noise is definitely from the hub area, consider a worn/dry/failing CV joint or (possibly) a bearing breaking up.

JV

[Wrightpayne]

I was thinking the same as John - might have to strip/check a few things. If you're undoing the big nut to check bearings then the driveshaft is easy to remove.

[John Vine]

I've just listened to your recordings again.  That regular tapping/clunking appears to occur at about the same frequency as the teeth on the crown wheel.  If so, that would suggest a problem inside the diff -- something loose, something broken?

JV

[Andy135]

#12, I got under the car again this morning and had my son turn the nearside wheel while I listened again. I noticed that if I held the offside drive shaft to stop it turning whilst the nearside was turned by my son, the clunk stops. I'd be interested in your point of view here as my knowledge of LSD's isn't deep enough to know whether this would also stop the crown wheel turning too? Or does the crown wheel still turn when one drive shaft doesn't? I didn't look to see if the prop was still rotating when the offside drive shaft was stopped, but if it was then would that suggest the crown wheel was turning too?

Here's a video of the clunk stopping when the offside drive shaft is prevented from turning.

And here's another video demonstrating the sound from underneath and next to the offside wheel hub.

While I was underneath I double-checked with a long screwdriver as a stethoscope and used my fingers to feel for the clunk again and it's clear that the sound and vibration is strongest at the offside wheel hub. Nothing on the diff casing or nearside drive shaft.

[John Vine]

#1: I have a theory but to avoid leading the witness I'll keep it to myself unless/until others suggest the same potential cause.

Taking stock, have any of our suggestions matched your suspected cause yet?

JV

 

[Andy135]

#14, yes, you and Ian have suggested what I was thinking. Either a collapsing bearing or a worn drive shaft joint, given the vicinity of these components to the apparent origin of the clunk.

I suspect I'll need to replace the bearing, then see if that cures the clunk. If not it'll be a drive shaft replacement. While the hub nut is off I'll pull the drive shaft and see what diff is in there.

Is there a guide or how-to for bearing replacement? I didn't build the car, so not sure of the relevant steps for a Caterham.

[Amos91]

How old is your car? There are two types of rear wheel bearing. The older roller bearing (similar to the fronts) and now a sealed NGK bearing which can be purchased with an updated bearing housing. 

Might sound silly, but is the hub nut tight?

[David aka Blue7]

I think the clue is in the hollow ringing sound amplified within the diff casing

[Andy135]

#16, 2008 kit, first registered 2012. Metric chassis Sigma Superlight 150. Which  version of the bearing would it need?

Good point about the hub nut. Not sure I have a socket to fit and my torque wrench is no longer calibrated, but might be worth a quick look just in case.

[John Vine]

#13:  Or does the crown wheel still turn when one drive shaft doesn't?

Yes, it'll continue to turn, as will the propshaft (and an LSD won't affect this).

JV

[Andy135]

#17, give us a clue then. I don't follow.

[Tom_Arundel]

I`m surprised that you can hold one drive shaft still and turn the other if you have a functioning LSD 

[Andy135]

#21 Tell me more then Tom.

[ScottR400D]

Depends what kind of 'LSD' it is. A gear one will allow that but if it's a plate diff you'd need to overcome the preload.  

[John Vine]

#23:  Unless your LSD is completely knackered, it looks as though you have a Quaife ATB. If you quote your chassis number to Martin Phipps (as Archivist), he could check factory records.

JV

[Amos91]

My factory built 2008 Sigma 150 came with a Quaife from factory. 

Mine has the older wheel bearing style but for about £100 you can buy the new style hub & bearing as a replacement.